The present invention relates to a blood bag label and a blood bag provided with such a label. The invention relates more particularly to a blood bag label avoiding the appearance of defects such as edging, folds, orange peel and “tunneling” when the blood bag is sterilized.
In the field of blood treatment, it is well known to store blood components in flexible plastic containers commonly known as blood bags. The blood bags are usually made of a flexible polyvinyl chloride (PVC) film comprising a plasticizer, generally di-2-ethylhexyl phthalate commonly known as DEHP (diethylhexyl phthalate).
In order to enable identification of certain information on the blood bag such as blood component, collection date, product code and batch number, etc., it is well known to provide labels for blood bags wherein the information is, in particular, represented by a bar code or the like.
Initially, the labels were made of paper. However, these paper labels had the disadvantage of not being strong enough and did not allow the transmission of gas.
In fact, it is known to treat the blood components stored in the blood bags by centrifuging them. Prior to use, the blood bags are sterilized, for example, using an autoclave sterilization process which is the most commonly used sterilization process. In particular, during these processes, the labels may be wetted and subjected to extreme temperatures of more than 100° C. in particular during sterilization. The paper labels may then crack or wrinkle during these processes. Cracking or wrinkling of a label may render the bar code of the label unreadable by a bar code reader, forcing an operator to manually enter data into a computer, or may even make it completely unreadable, which increases the risk of errors. Labels may also come off completely or partially during sterilization, resulting in a risk of data loss.
In addition, the blood bags must allow the transmission of gas through the pocket to maintain the viability of blood cells stored therein. In this respect, it is necessary that the bag should allow the carbon dioxide to escape from the blood bag and allow the passage of oxygen into the bag.
In order to overcome the disadvantages of paper labels for blood bags, synthetic labels have already been devised which are easy to print, resistant to sterilization conditions and allow gaseous exchanges with the contents of the blood bags. This is the case with U.S. Pat. No. 5,314,421 and European patent application EP 2,806,004, in particular.
Document U.S. Pat. No. 5,314,421 discloses a blood bag label comprising a microporous plastic film comprising a matrix of interconnected pores to allow gas to enter and to exit the blood bag through a labeled area. The label includes a pressure-sensitive adhesive on a surface to enable writing on the label. Furthermore, the pores allow ink to be absorbed at least on an outer surface of the label to allow writing on the label, in particular writing a barcode. More particularly, the microporous plastic film consists of a microporous polyolefin film marketed under the Teslin brand by the company PPG Industries.
EP 2 806 004 also discloses a blood bag label comprising a flexible support and a pressure-sensitive adhesive layer deposited on one of the surfaces of the support. The support consists of a polypropylene film with a thickness of 80 μm, while the adhesive is obtained from a polyester-based resin comprising an amorphous polyester which has a glass transition temperature of between −30° C. and 7° C. and a crosslinking agent.
The latter blood bag labels, although more resistant than paper labels, have the disadvantage of providing surface defects such as edging, folds, orange peel and “tunneling” when the blood bag is sterilized, making the labels unreadable for a barcode reader. “Tunneling” is understood to mean a significant fold of the label which then forms a kind of tunnel.
Document US2016/0319164 also discloses a label polypropylene for a blood bag wherein the label is obtained in a microporous polypropylene film with a porosity of between 2500 and 4771 Gurley seconds, and wherein the polypropylene film exhibited a shrinkage of less than 2% in the machine direction and 4 to 6% in the transverse direction after exposure to a temperature of 121° C. for 30 minutes. When exposed to sterilization conditions, the label has withdrawal characteristics that closely match the withdrawal characteristics of the blood bag.
However, these labels do not make it possible to sufficiently reduce the surface defects of the edging, folds, orange peel and tunneling type when the blood bag is sterilized.